There is an increasing demand to automate moving machinery that traditionally requires a human operator. There are several reasons for this. Unlike a human operator, automated machinery remains consistently productive regardless of environmental conditions and prolonged work hours. Automated machinery is also ideal for applications where conditions are unsuitable or undesirable for humans. Further, automated machinery enables more accurate operation and compensates for lack of operator skill.
The work cycles of different types of machines may include similar requirements. Some machines, including earth, asphalt, and trash compactors, may repeatedly traverse a site until the material is compressed to a desired degree. Other types of machines, such as lawn mowing machinery, may traverse an area only once during a work cycle. During autonomous operation, these machines require means to determine their position, the area to be traversed, an optimal path to follow while traversing the area, and means to control their movement while traversing the path.
As a mobile machine traverses an area, a series of paths for the machine to follow is typically determined. Some types of machines are capable of performing a work function, such as compacting material, while traveling bi-directionally, i.e., in either a forward or reverse direction. Other machines are capable of performing a work function in one direction only and must be turned to a new heading to move along another path. Regardless of whether the machine is capable of performing a work function in one direction or bi-directionally, means for transitioning from a first path to a second path is required.
In the prior art, systems for achieving a desired degree of compaction or desired site topography using mobile terrain-shaping and material compacting machinery are known. These systems are shown, for example, in U.S. Pat. Nos. 5,631,658; 5,493,494; 5,471,391; and 5,646,844. In these patents, the difference between the actual site topography and the desired site topography is determined on a continual basis and this information is provided to an operator via a real-time display. The machines typically travel along a series of paths over the area. These patents do not, however, disclose means for determining an efficient transition from one path to another as the machine traverses the area.
Accordingly, the present invention is directed to overcoming one or more of the problems as set forth above.